Opus eats a lot of tokens. It's not usable on the pro plan for any kind of serious work. Switched to Sonnet before going back onto Max. It's not clear however, how to evaluate the difference between Sonnet and Opus. I do not have my own dataset.
There was this thread from Thariq from Anthropic. Contained some good stuff on prompts and spec writing here. Prompt essentially what I've done before about asking Claude to interview you. This works if you know what you're at and it at least forces thinking about topics if they are new to you. However, I'm not sure it's the best way to learn something.
Would be great to have a skill to ask Claude to walk me through the code so I understand it better. This could be obsolete though if code review becomes abstracted away. We need new ways to understand the codebase such as diagrams or clean specs.